1. Field Of The Invention
The present invention relates to a linkage assembly for locking a traveling rail. More particularly, the present invention relates to a roller linkage for selectively locking the traveling member.
2. Description Of The Prior Art
It is often desirable to lock a traveling member to prevent movement of the traveling member. One such an example is an industrial weld gun apparatus. Typically, the weld gun is fixedly secured on a rail. The rail extends from a housing and is moveable with respect thereto to position the weld gun in the appropriate location to preform its welding function. Once the rail and gun are extended to the desired location, the rail member is stopped to prevent movement thereof with respect to the housing while performing the welding function. Typically, the rail is positioned and locked by electronic controls. These electronic controls are expensive and not effective to keep the rail locked in the event of a power failure.
The U.S. Pat. No. 4,541,299 to Kanaya et al discloses a roller linkage assembly for transmitting forces to secure a traveling member and prevent relative movement between two members. Specifically, the Kanaya patent shows a telescoping steering shaft assembly. An upper shaft extends from a cylindrical portion of a lower shaft. The upper shaft telescopes relative to the lower shaft to permit telescopic movement: of the steering assembly. An actuator handle is connected to an actuator rod. The actuation rod imparts a force on a plurality of spherical rollers. When actuated, the spherical rollers which are housed in the upper shaft engage the cylindrical portion of the lower shaft to prevent relative telescoping movement between the upper shaft and the cylindrical portion of the lower shaft. When in the locked position, forces upon the upper or lower shaft are transmitted to the actuator rod.
U.S. Pat. No. 1,802,975 to Kintzele issued Apr. 28, 1931 discloses an assembly for locking one member with respect to a second member. Specifically, the assembly includes a locking mechanism for preventing relative movement between a traveling member and a fixed member. The traveling member includes a plurality of spherical rollers housed in a housing. An actuator member imparts a force to the spherical rollers which engage a stationary member. When the actuator is moved, thereby moving the roller into the stationary member, the traveling member is locked and can not move relative to the stationary member. Any force imparted to the stationary or moveable members is transmitted through the rollers and to the actuator.